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09/03/12 4:00 PM ET

Arias sidelined with tight calf muscle

SAN FRANCISCO -- Left-handed-hitting Brandon Crawford got the start at shortstop against Arizona Diamondbacks southpaw Patrick Corbin on Monday, with red-hot backup Joaquin Arias getting a day off to nurse a tight calf muscle.

Arias, who was out of the lineup Thursday after getting hit by a pitch on his left wrist, began to feel tightness in his calf in Sunday's game against the Cubs. Arias is coming off an August in which he led the Majors with a .417 average while driving in 15 runs and hitting three homers.

"His wrist is fine, but his calf is a little tight, so we're being a little cautious with him," manager Bruce Bochy said. "He felt it yesterday in the game, but he stayed in until I made the double-switch. It's a little tight today, so he's getting a break today. He is available to pinch-hit, but we want to get him some rest out there today."

Lopez is central to success of Giants' bullpen

SAN FRANCISCO -- The Giants bullpen's solid performance on the recent six-game road trip played a big role in the team picking up five wins, with the Giants' relievers allowing one run in 18 innings in those wins.

On Sunday against the Cubs, the bullpen pitched four scoreless innings after starter Matt Cain allowed five runs in five innings in the Giants' 7-5 comeback win.

"I'm really proud of those guys," manager Bruce Bochy said. "Yesterday, they saved us. After Cain went five, they gave us four great innings. And really, none of them are getting overworked. They're getting it done."

Entrenched in the strong play of the Giants' bullpen has been Javier Lopez, who has thrived in late-inning situations since joining Bochy's new closer-by-committee setup. Lopez has not given up a run in his past 23 outings (15 innings), and in the recent road trip, he notched two saves and two holds in four appearances -- all on just 36 pitches.

"He's really pitching with a lot of confidence and hitting his spots, not just against lefties but against righties, too," Bochy said of Lopez. "He's really pounding the strike zone."

Bochy expects Jean Machi, who joined the club on Saturday after having his contract purchased from Triple-A Fresno, to play a role down the stretch, though he said Machi would likely not pitch on Monday. Machi had been serving as Fresno's closer this season, and the 30-year-old reliever has never appeared in the Major Leagues.

"He was closing in Fresno, and he did a nice job there," Bochy said. "I saw him in the spring, and he's got a nice fastball, with a slider [and] a split. He has the equipment to pitch up here. He's going to be out there some time, I just can't tell you when."

Giants' slate is stacked with NL West foes

SAN FRANCISCO -- Returning from a six-game road swing against two National League Central opponents in the Astros and Cubs, the Giants have begun a final stretch of the season in which the schedule will only feature NL West foes.

"I'll be honest, it'll be nice to not have to go to the East Coast right now and stay within the division, but we have a lot of work ahead of us, we know it," manager Bruce Bochy said.

Beginning with the three-game series against the Arizona Diamondbacks that kicked off on Monday, the Giants will only play one opponent with a winning record -- the Dodgers, who entered Monday with a 4 1/2-game deficit behind the first-place Giants.

The D-backs entered Monday's game three games below .500, while the Padres wrapped up their second straight winning month in August to improve upon their 20-41 start to the season. The Rockies, meanwhile, had won six of their past 10.

"We're in September now, and now it's the stretch drive and we're in the division," Bochy said. "You're hoping our home play picks up like it was early in the season, and we're going to be playing some teams who are playing very well. Not just Arizona and, of course, L.A., but also San Diego and Colorado, they're playing good baseball."

Jay Lee is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.